The present invention relates to an apparatus for testing spherical objects. More specifically, the present invention relate to an apparatus for testing the physical properties, Coefficient of Restitution, and quality of golf balls.
Various types of equipment have been used for testing the physical properties of objects such as golf balls. One type of equipment employs a mechanical device that is programmed to swing a golf club in a repeated pattern to drive balls from a fixed tee position in order to test for travel distances of the balls. Other types of equipment use a propelling mechanism to launch a ball through a predetermined path, along which sensors are provided for recording the flight of the ball.
One such device employs a barrel into which a golf ball can be mounted via a hinged cover in the side of the barrel. This type of device uses a sealing ring within the bore of the barrel to hold the ball in position. After closing the hinged cover, a pneumatic charge is delivered to the barrel so as to push the ball through the sealing ring, and out of the barrel, at a high speed. However, this type of mechanism is not able to consistently launch balls at a given velocity. This is typically due to the fact that the threshold for passing the ball through the sealing ring varies for each ball being fired. Typically, this causes an inconsistency from between xc2xd to 2 feet/second. Because the sealing ring causes an inconsistency in the velocity of the ball, it becomes difficult to adjust the velocity of the ball to test at different speeds. When testing velocity dependant physical characteristics, such as Coefficient of Restitution, this is often desirable.
When measuring the characteristics of a ball, it is desirable to propel the ball at a known and consistent velocity. This can be important when measuring many ball characteristics, such as distance, coefficient of restitution, durability, or quality testing. Specifically, when testing coefficient of restitution, it is particularly important to be able to propel a set of balls at a consistent velocity.
Current devices have many other drawbacks. These devices are typically bulky, and require many components. In addition, the devices typically require balls to be manually fed and recovered, resulting in significant downtime and increased operator time. Additionally, current devices do not provide a reliable apparatus or method for testing at different ball velocities. Furthermore, existing devices do not conveniently allow for the testing of differently sized balls.
A continuing need exists for an apparatus for accurately testing the physical properties of golf balls while minimizing the time and number of components required.
In a preferred embodiment, the present invention comprises an apparatus for measuring the physical properties of a golf ball. The apparatus comprises a striking surface, and a propelling device facing the striking surface. The propelling device preferably fires a golf ball towards the striking surface. In a preferred embodiment, the propelling device comprises an interchangeable barrel system. A sensing unit is located between the striking surface and the propelling device. The sensing unit preferably has a measuring field covering a space between the propelling device and the striking surface. Preferably, the sensing unit is capable of measuring the time it takes for the golf ball to travel a distance in the measuring field of the sensing unit. A computing unit is communication with the sensing unit, and is preferably capable of calculating the Coefficient of Restitution of the golf ball.
In a preferred embodiment, the interchangeable barrel system comprises an inner barrel and an outer barrel. The inner barrel has a sliding connection with the outer barrel, and is preferably interchangeable based on the size of the golf ball being fired. The outer barrel preferably has an opening that allows a golf ball to be loaded into the barrel system.
A golf ball is loaded into the barrel system by inserting a golf ball through the opening in the outer barrel. The inner barrel, which has an angled leading edge, then captures the ball with the assistance of a tubular backstop that is attached to the outer barrel. The leading edge of the inner barrel preferably has an angle of between 30 and 50 degrees.
In a preferred embodiment, the diameter of the inner barrel is between about 0.038 and 0.042 inches greater than the diameter of the golf ball. The diameter of the outer barrel is between about 0.030 and 0.050 inches greater than the diameter of the inner barrel.
In a preferred embodiment, the entire barrel system is positioned at an angle relative to a horizontal plane. The angle is preferably chosen to prevent the golf ball from falling out of the barrel system. In a preferred embodiment, this angle is preferably between 0.01 and 3.0 degrees.
In a preferred embodiment, the barrel system and the striking surface are positioned at an angle that is not orthogonal. The angle is preferably determined in order to prevent a fired golf ball from re-entering the barrel system after rebounding off of the striking surface. In a preferred embodiment, the angle between the propelling device and the striking surface is between 90 and 95 degrees.
Preferably, the barrel system includes a fast acting valve that closes substantially as soon as the golf ball leaves the barrel system. This prevents a propellant from affecting the flight path of the ball or, in some embodiments, the sensing unit.
In a preferred embodiment, the sensing unit comprises at least two sensors. One of the sensors may be placed substantially close to the striking surface in order to calculate the impact duration between the golf ball and the striking surface.
The fired golf balls are collected using a chamber floor that employs gravity to direct the balls towards an exit chute. The exit chute directs the balls towards a pneumatically controlled return system. The return system has a valve that either directs balls back to the barrel system, or to a collection device.
The present invention also comprises a method of measuring the Coefficient of Restitution (COR) of a plurality of golf balls. The method includes providing a propelling device, a striking surface, and a sensing unit located between the striking surface and then propelling device. Golf balls are first fired from the propelling device towards the striking surface. Once the balls are fired, the sensing unit measures the velocity of the balls before it contacts the striking surface. The sensing unit then measures the velocity of the balls after it rebounds from the striking surface. Any desired method may then be used to determine the COR of the golf ball.
In a preferred embodiment, the method also includes collecting the fired golf balls after they rebound from the striking surface. The balls may then be redirected to either the propelling device or a collection device. If the balls are directed towards the propelling device, they are once again fired and their velocities are measured both before and after contacting the striking surface. In another embodiment, the contact time of the golf ball may be determined using a substantially similar method.
Other and further aspects of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawings, which by way of illustration, show preferred embodiments of the present invention. Other embodiments of the invention embodying the same or equivalent principles may be used and structural changes may be made as desired by those skilled in the art without departing from the present invention and the purview of the appended claims.